In the conventional communication system that includes an RF reader/writer and an RFID tag, there have been proposed various diagnostic functions concerning communication. For example, Japanese Unexamined Patent Publication No. 2005-322029 introduces a system that facilitates specification of a correspondence error factor between the RF tag and the reader/writer.
There is a description about the structure that the CPU diagnoses whether an “RF tag reader/writer” device has abnormality or the state of wireless communication to the RF tag has abnormality and the CPU notifies a diagnosis result to a high-order device.
The structure has a first step in which the CPU first transmits data to a wireless communication device and diagnoses presence or absence of abnormality in the wireless communication device based on presence or absence of a response to the data transmission, and a second step in which when the wireless communication device has been diagnosed as “normal” in the first step, the CPU transmits a wireless-communication execution command to the RF tag and diagnoses the state of wireless communication to the RF tag based on a result of response to the transmission. When the wireless communication device has been diagnosed as abnormal in the first step, the CPU notifies the abnormality, and when the wireless communication device has been diagnosed as abnormal in the second step, the CPU notifies the abnormality.
Japanese Unexamined Patent Publication No. 2011-59240 discloses the following system. In a reader/writer having a reference tag for test and an exclusive antenna circuit for corresponding with the reference tag, when the reader/writer cannot receive a reply signal from the reference tag from the exclusive antenna circuit, the CPU decides that the reader/writer device is in trouble. On the other hand, when the reader writer has been able to receive the reply signal from the reference tag from the exclusive antenna circuit, the CPU decides that the reader/writer device is normal.